This invention relates generally to a dual wall exhaust liner for a gas turbine engine. More particularly, this invention relates to a dual wall exhaust nozzle and/or duct closeout.
A gas turbine engine typically includes a plurality of turbine blades that transform energy from a mainstream of combustion gasses into mechanical energy that rotates and drives a compressor. The combustion gases exit the gas turbine engine through an exhaust nozzle. The exhaust nozzle assembly typically includes a hot side liner exposed to hot combustion gases and a cold side liner spaced radially apart from the hot side liner. The space between the hot side liner and the cold side liner defines a passage for cooling air. The cooling air is provided along the hot side liner to protect against the extreme heat generated by the combustion gases.
The hot side liner will often include a plurality of openings for communicating cooling air along an interior surface of the exhaust nozzle. The cooling air forms an insulating layer along the interior surface of the exhaust nozzle that protects the hot side liner. The hot side liner operates at a temperature much greater than that of the cold side liner. Accordingly, the cold side liner and hot side liner expand and contract differently in response to thermal conditions. The relative thermal expansions and contractions can generate stresses and strains in the hot side and cold side liner.
Further, it is known to provide for both stationary and articulating exhaust nozzle and ducts. Articulating exhaust nozzles and ducts allow for selectively directing combustion gases. The articulated exhaust nozzle and ducts includes several segments movable relative to each other. The interface between each segment requires that the air passage defined between the hot side and cold side liners be closed off. Further, it is desirable that the interface is cooled and sealed to contain combustion gases within the exhaust nozzle. Closing off the air passage at each interface joint complicates localized cooling between movable segments. The dynamic nature of the interface between movable segments creates a challenge to cooling of the hot side liner.
Accordingly, it is desirable to develop a dual wall exhaust liner closeout that accommodates differing thermal expansions and provides cooling airflow at an interface between movable segments of an exhaust nozzle and or duct assembly.